1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a stacked type image sensor including a color separation element and an image pickup apparatus including the stacked type image sensor.
2. Description of the Related Art
Color displays and color image sensors may display multicolor images and detect colors of light incident thereon by using color filters. Color displays and color image sensors may use an RGB color filter scheme in which, for example, green filters are disposed in two of four pixels and blue and red filters are disposed in the other two pixels. Alternatively, a CYGM color filter scheme, in which filters of complementary colors, i.e., cyan, yellow, green, and magenta, are respectively disposed in four pixels, may be used.
However, since the color filters absorb all colors of light except for a filtered color, the light use efficiency of the color filters may be low. For example, since RGB color filters may transmit only about ⅓ of incident light and absorb about ⅔ of the incident light, the light use efficiency of the RGB color filters may only be about 33%. Therefore, most of the optical loss of the color filters of the color displays or the color image sensors may be caused by the color filters.
Attempts have been made to use color separation elements rather than the color filters to increase light use efficiency of the color displays and the color image sensors. The color separation elements may separate colors of incident light based on diffraction or refraction characteristics of light varying according to wavelengths of light, and may transmit the separated colors to pixels of corresponding colors. Therefore, the light use efficiency may be higher when using the color separation elements than the color filters. However, since color separation efficiency of color separation elements may change according to incident angles of light, color separation efficiency of a plurality of pixels of an image sensor may vary, and thus, the plurality of pixels may have different sensitivities.